I'm not sure about this one. The idea is to start a snapshot
commit with the SNAP_CREATE_ASYNC ioctl, and wait for it with
the WAIT_SYNC ioctl. I'm not sure that modifying
btrfs_ioctl_vol_args is the way to do that. That technically
changes the ABI (albeit in a way that nobody will actually
notice). I'm not sure it's worth creating a second, different
ioctl_async_vol_args struct and complicating ioctl.c funcs.
OTOH, a WAIT_SYNC without an explicit trans will almost always
accomplish the same thing. Worst case we wait a bit longer than
needed (for a second racing commit to complete).
Signed-off-by: Sage Weil <sage@xxxxxxxxxxxx>
---
fs/btrfs/ioctl.c | 7 +++++++
fs/btrfs/ioctl.h | 4 +++-
2 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 7ea4ff0..fd824a7 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -885,6 +885,13 @@ static noinline int btrfs_ioctl_snap_create(struct file *file,
async ? &transid : NULL);
fput(src_file);
}
+ if (!ret && async) {
+ struct btrfs_ioctl_vol_args __user *user_vol_args = arg;
+
+ if (copy_to_user(&user_vol_args->transid, &transid,
+ sizeof(transid)))
+ return -EFAULT;
+ }
out:
kfree(vol_args);
return ret;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index d9169d8..4f7fe37 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -22,12 +22,14 @@
#define BTRFS_IOCTL_MAGIC 0x94
#define BTRFS_VOL_NAME_MAX 255
-#define BTRFS_PATH_NAME_MAX 4087
+#define BTRFS_PATH_NAME_MAX 4071
/* this should be 4k */
struct btrfs_ioctl_vol_args {
__s64 fd;
char name[BTRFS_PATH_NAME_MAX + 1];
+ __u64 transid;
+ __u64 reserved;
};
#define BTRFS_INO_LOOKUP_PATH_MAX 4080
--
1.6.6.1
--
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